The present invention relates to a pusher which pushes such an object as parts and a work of a machine uniformly using front end of a plurality of pistons projecting at its front surface.
In a conventional steel plate slitter to cut a wide band steel plate into a plurality of narrow band steel plates, as shown in FIG. 1, two arbors 21, 22, are arranged in parallel on the vertical plane and each of the arbors 21, 22 is provided with a slipping-proof part 23 of large diameter at one end and a threaded part 24 of small diameter at other end. Annular or cylindrical spacers 25 and annular plate form cutters 26 are fitted to each of the arbors 21, 22 and a nut 27 threadably engaged with the threaded part 24 of each of the arbors 21, 22 is tightened, so that a plurality of the spacers 25 and a plurality of the cutters 26 are grasped between the nut 27 and slipping-proof part 23 of each of the arbors 21, 22 and a plurality of the cutters 26 are mounted on required positions of each of the arbors 21, 22 and bottom end of each cutter 26 of the arbor 21 on upper side and top end of each cutter 26 of the arbor 22 on lower side are spaced by a required gap.
In this constitution, however, since the cutter 26 are tightened by the nut 27 threadably engaged with the threaded part 24 of the arbor, if threads of the nut 27 and/or the threaded part 24 are not accurately finished or if spacer abutting surface of the nut 27 and/or cutter abutting surface of the spacer 25 are not perpendicular to the arbor axial direction but slanted, the abutting surface of the cutter 26 with the spacer 25 is not uniformly pushed and the cutter 26 is not perpendicular to the arbor axial direction but slanted thereto. If the cutter 26 is slanted, the cutting line of the steel plate is not linear but meanders.
Since the nut 27 threadably engaged with the threaded part 24 of the arbor abuts on the spacer 25, large force is required to tighten the nut 27 and therefore it is very difficult to increase the pushing force against the cutter 26 and much trouble is required to adjust the gap between the upper and lower cutters 26, 26. If the gap between the upper and lower cutters 26, 26 is not suitable, the cutting of the steel plate is not performed smoothly thereby burr may be produced at the cutting surface of the steel plate. Moreover, if pushing force or tightening force of the cutter 26 is small, the cutter 26 is loosened and trouble to adjust the gap is required again.